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Forecasts show the mid-Atlantic is likely to take the biggest wallop; effects on Northeast are less certain

(CNN)A nasty snowstorm is expected to bury the Washington, D.C., area beginning Friday, and possibly surpass totals for a benchmark 1922 storm.

The National Weather Service on Wednesday said it expected between 12" and 24" of snow to fall in the District of Columbia, Baltimore and surrounding counties by late Saturday. Those totals could be adjusted up or down depending on the exact track of the storm, which is targeting the mid-Atlantic region.

CNN meteorologist Tom Sater says a computer model shows the capital will be the bull's-eye for up to 30" of snow by Sunday.

Tens of millions of East Coast residents could be affected by the storm system, which will be ushered by ice. "Then the winds kick in," said Sater, downing branches and power lines.

Blizzard conditions expected

A blizzard watch is set to begin Friday afternoon and extend through late Saturday. But that could be upgraded to a warning by Thursday. The worst of the storm is expected Friday night through the day Saturday.

"Heavy and blowing snow will cause dangerous conditions and will be a threat to life and property," the weather service said. "Travel is expected to be severely limited if not impossible during the height of the storm ..."

Communities along the East Coast were preparing for the wintry onslaught, piling up salt and positioning snow plows. A light snow fell Wednesday night in the capital, a precursor to the expected big event this weekend.

Virginia State Police reported 163 accidents statewide during the precipitation.

Police were investigating whether a single-fatality crash in Bedford County was related to the weather. A state trooper was taken to a hospital for minor injuries after being struck while responding to a crash on I-495 in Fairfax County. A van swerved to avoid another car and struck the trooper outside his vehicle, officials said.

"Roads continue to be slick and treacherous, particularly in northern and western Virginia," said State Police spokeswoman Corinne Geller.

Even the commander in chief had to reckon with the wintry mix. Video shows President Barack Obama's motorcade using hazard lights as it made its slippery way from Joint Base Andrews to the White House. He was unable to fly on Marine One because of the weather.

The manager at Strosniders Hardware in Silver Spring, Maryland, told CNN affiliate WJLA that customers had bought almost all of his ice melt chemical.

"They know (the storm is) coming," Roy Washington said. "They hear the forecast, and they want to be prepared for it."

Oklahoma, Arkansas, Kentucky and North Carolina will see ice as the storm moves east Thursday into Friday.

Talk of a possible blizzard came on the same day the federal government reported that 2015 was the Earth's warmest since record-keeping began in 1880. But big snows can occur even in the warmest years. Despite the snowiest winter on record for Boston, the state of Massachusetts still ended 2015 with temperatures far above average.